The present invention has to do with the features of a status LED indicator. More particularly, this invention describes a new and useful sleep-mode status indicator system for laptop computers.
Saving electrical power has been a very important goal ever since the birth of battery-operated portable devices. For example, for laptop computers, one efficient way is to apply battery power only to the parts of a device in use, and at the same time to withhold power from those parts of a device not in use. The early portable devices, however, had a simple ON/OFF arrangement in which full battery power was available for use when the devices were ON and the battery power was completely shut off when the devices were OFF. Information such as re-usable software programs and data saved in the semiconductor memories became lost once the devices were turned OFF. To use the programs and data again, additional power and time must be used to load them back into the semiconductor memories. Some later portable device used non-volatile semiconductor memories so that the saved information remains intact even when the devices were turned OFF; some other portable devices used stand-by power adapted to keep the memories refreshed when the devices were OFF.
Today""s laptop computers have complicated circuitry because of their additional peripheral units such as floppy disk, hard disk, PCMCIA and CD drives. To efficiently manage the use of electrical power, arrangements have been devised to monitor various functions inside a laptop computer. The computer is intelligent enough to apply battery power only to internal circuits and sub-systems that are deemed xe2x80x98in usexe2x80x99 and at the same time to withhold power from those circuits and sub-systems that are deemed xe2x80x98idlexe2x80x99. Sometimes the power is not completely withheld from the xe2x80x98idlexe2x80x99 circuitry but the power supply is merely reduced due to its entry into a low power consumption mode. Either way, the power management arrangement inside the laptop computer maximizes the computer""s power savings and lengthens the duration the laptop computer can operate using batteries.
The electrical state of the computer when the power management arrangement deprives or reduces electrical power supplied to the xe2x80x98idlexe2x80x99 circuitry and sub-systems is generally referred to as the sleep mode. During sleep mode, the arrangement further monitors the activities in the computer in order that power can be applied immediately when needed. One way a laptop computer enters into the sleep mode is through user inaction. For example, when there is no user key entry for a pre-determined duration, display circuitry and related-subsystems are then shut off, and relevant programs and data are saved. Another way is through user issuance of a sleep command, and another way is through the detection of battery charge below a set level.
To awaken the computer from sleep mode, a typical way is by pressing any key on the keyboard. In this manner, relevant programs and data need not be re-loaded from hard disk and power to an otherwise idle display is conserved.
A sleep-mode indicator typically identifies to users that the laptop computer is in sleep mode. One such indicator is a blinking LED (light emitting device) located on a computer housing for convenient observation. For example, a typical sleep-mode indicator for Apple Macintosh PowerBook(copyright) computers is a blinking LED indicator subjected to identical electrical energy pulses at about one second apart and for a duration of about 40 msecs. FIG. 1 is a waveform chart that illustrates the identical electrical pulses that generate a prior art sleep-mode indicator blinking effect for the laptop computers. In this chart, the LED is driven with 6 mA of current for 40 msecs once a second.
Unfortunately, the LED blinking effect resulting from a once a second, identical electrical energy pulses does not provide the best pattern that is visually appealing to the users. A better and more improved status LED indicator is needed. More particularly, a better and more improved sleep-mode indicator system is therefore needed and duly described herein.
Therefore, it is an aspect of the present invention to provide a better and more improved status LED indicator. It is another aspect of the invention to provide a sleep-mode indicator for an electronic device such as a laptop computer that the indicator generates a visually appealing blinking pattern to the users. It is another aspect of the present invention to provide a LED blinking pattern along with varied intensity that in combination mimics the rhythm of breathing. It is yet another aspect of the present invention to provide an electrical apparatus that generates a sleep-mode indicator blinking pattern based on a sinusoidal function using PWM (pulse width modulation) designs.